This makes us derive ranges for loop IVs in EVRP using
adjust_range_with_scevs. It also allows us to derive ranges from
conditions in loop preheaders (I think that's still broken because
we force simple preheaders and predecessor search doesn't follow
forwarders -- sth for a followup).
Bootstrap and regtest running on x86_64-unknown-linux-gnu.
Richard.
2016-10-21 Richard Biener <rguent...@suse.de>
* tree-vrp.c (evrp_dom_walker::before_dom_children): Ignore
backedges when identifying the single predecessor to take
conditional info from. Use SCEV to get at ranges for loop IVs.
Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c (revision 241400)
+++ gcc/tree-vrp.c (working copy)
@@ -10693,12 +10693,29 @@ edge
evrp_dom_walker::before_dom_children (basic_block bb)
{
tree op0 = NULL_TREE;
+ edge_iterator ei;
+ edge e;
push_value_range (NULL_TREE, NULL);
- if (single_pred_p (bb))
+
+ edge pred_e = NULL;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ /* Ignore simple backedges from this to allow recording conditions
+ in loop headers. */
+ if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest))
+ continue;
+ if (! pred_e)
+ pred_e = e;
+ else
+ {
+ pred_e = NULL;
+ break;
+ }
+ }
+ if (pred_e)
{
- edge e = single_pred_edge (bb);
- gimple *stmt = last_stmt (e->src);
+ gimple *stmt = last_stmt (pred_e->src);
if (stmt
&& gimple_code (stmt) == GIMPLE_COND
&& (op0 = gimple_cond_lhs (stmt))
@@ -10715,7 +10732,7 @@ evrp_dom_walker::before_dom_children (ba
op1 = drop_tree_overflow (op1);
/* If condition is false, invert the cond. */
- if (e->flags & EDGE_FALSE_VALUE)
+ if (pred_e->flags & EDGE_FALSE_VALUE)
code = invert_tree_comparison (gimple_cond_code (stmt),
HONOR_NANS (op0));
/* Add VR when (OP0 CODE OP1) condition is true. */
@@ -10743,11 +10760,7 @@ evrp_dom_walker::before_dom_children (ba
}
/* Visit PHI stmts and discover any new VRs possible. */
- gimple_stmt_iterator gsi;
- edge e;
- edge_iterator ei;
bool has_unvisited_preds = false;
-
FOR_EACH_EDGE (e, ei, bb->preds)
if (e->flags & EDGE_EXECUTABLE
&& !(e->src->flags & BB_VISITED))
@@ -10761,12 +10774,24 @@ evrp_dom_walker::before_dom_children (ba
{
gphi *phi = gpi.phi ();
tree lhs = PHI_RESULT (phi);
+ if (virtual_operand_p (lhs))
+ continue;
value_range vr_result = VR_INITIALIZER;
if (!has_unvisited_preds
&& stmt_interesting_for_vrp (phi))
extract_range_from_phi_node (phi, &vr_result);
else
- set_value_range_to_varying (&vr_result);
+ {
+ /* When we have an unvisited executable predecessor we can't
+ use PHI arg ranges which may be still UNDEFINED but have
+ to use VARYING for them. But we can still resort to
+ SCEV for loop header PHIs. */
+ set_value_range_to_varying (&vr_result);
+ struct loop *l;
+ if ((l = loop_containing_stmt (phi))
+ && l->header == gimple_bb (phi))
+ adjust_range_with_scev (&vr_result, l, phi, lhs);
+ }
update_value_range (lhs, &vr_result);
/* Mark PHIs whose lhs we fully propagate for removal. */
@@ -10778,7 +10803,8 @@ evrp_dom_walker::before_dom_children (ba
edge taken_edge = NULL;
/* Visit all other stmts and discover any new VRs possible. */
- for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
+ !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
tree output = NULL_TREE;
